How to compute NCr % mod when mod is a prime power

Revision en1, by Ma7moud, 2023-05-29 00:48:58

hello people! https://www.codechef.com/problems/SANDWICH I really tried to solve this problem I know I must factorize mod to its prime powers And solve some equations using crt but I don't know how to calculate mod inverse for x! Mod p^e where p is a prime p | mod since the gcd between x! and p is not equal to one any know how to calculate it ?

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en1 English Ma7moud 2023-05-29 00:48:58 409 Initial revision (published)